TPN calculation

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braingel

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I have a question on TPN calculation, I know the concept but somehow getting confused with total volume and the stock solution

so say the order is for
15% amino acid
10% dextrose
10% lipids

Stock solution that pharmacy carries
10%(1000ml) amino acid
40%(1000ml) dextrose
20% (250ml) lipids

please tell me how you guys would have done this
Thankx

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Call me an ignorant P1, but how are you supposed to make a 15% Amino acid solution if you only have the more dilute 10% solution?
 
Good call by the p1. And what total volume do you want?
 
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I have a question on TPN calculation, I know the concept but somehow getting confused with total volume and the stock solution

so say the order is for
15% amino acid
10% dextrose
10% lipids

Stock solution that pharmacy carries
10%(1000ml) amino acid
40%(1000ml) dextrose
20% (250ml) lipids

please tell me how you guys would have done this
Thankx

Was this how the TPN order was written (above)? Or did it have instructions like 200mL of 15% amino acids?

If it was written ---- 200mL of 15% amino acids - then that means you need 30gm of proteins this is the equivalent of 300mL of the 10% amino acid stock that the pharmacy has on formulary. Hope this helps as it is unclear to me what the question was.

Sometimes, they break it down according to % AA/Lipids/Dextrose based on total calories needed. At which point you would need to figure out the number of calories for each as a % of the total calories. From there figure out how many grams of you need. After which you should be able to figure out how many mLs you need for the TPN bag. Lastly, you could add lytes and fluid according to daily fluid requirement.

Hope this helps.
 
Yep, you need to know the volume of the TPN (or the total calories). Then you can convert to grams and use the appropriate amount of each stock solution.

Just remember not to add any Serretia to that...
 
I would like to thank you guys for your reply
I believe the total volume was 2L. This came across to me by a pharmacist while on rotation.
and my other question is that can you make 10% lipids from 20% stock solution? I mean wuld you add sterile water to make up the total volume of 250ml?
 
Our lipids are in a separate container. We have 20%, but the nurses can just administer whatever amount necessary to obtain the number of grams/calories needed.
 
Yep, you need to know the volume of the TPN (or the total calories). Then you can convert to grams and use the appropriate amount of each stock solution.

Just remember not to add any Serretia to that...

:(
 
This came across to me by a pharmacist while on rotation.
and my other question is that can you make 10% lipids from 20% stock solution? I mean wuld you add sterile water to make up the total volume of 250ml?

Is this a joke? You're on rotations and cannot figure this out? This has to be a troll.
 
Hmmm... he's misrepresenting himself as a pharmacist which implies knowledge of said subjects. It could be that he is a P1 or 2 who just hasn't covered the subject. Some schools do that one day a week rotation.

:rolleyes:


Oh good call. Braingel if you're a P1 I apologize. To answer your question. You can make a 250ml 10% fat solution by using 125ml of SWFI and 125ml of intralipid 20%. Ask your preceptor to explain the math if you're not sure.

If you're a P4 god help us all.

Lastly, making 10% fats like this is not good practice, so I hope this problem is theoretical.
 
Are you guys serious?

First of all, get a totol TPN volume. Let's say 2 liters.
Then, convert % to gm for each macronutrients.
300gm a.a
200gm dextrose
200gm lipids (10% x 2 liters)

Simple math follows for lipids calc...
if you have intralipid 20% in stock,
100ml/20gm x 200gm = 1000ml of 20% intralipid

So you don't need to dilute? or anything. I hope this is not a real TPN order.
 
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